U.S. patent number 4,577,646 [Application Number 06/602,425] was granted by the patent office on 1986-03-25 for process for improving the fillability of tobacco.
This patent grant is currently assigned to H.F. & Ph.F Reemtsma GmbH & Co.. Invention is credited to Klaus-Dieter Ziehn.
United States Patent |
4,577,646 |
Ziehn |
March 25, 1986 |
Process for improving the fillability of tobacco
Abstract
Process for improving the fillability of tobacco, such as cut
tobacco leaves or ribs and tobacco additives by treating the
tobacco in an autoclave with a containing nitrogen and/or argon at
pressures up to 1000 bar, with subsequent decompression and a gas
heat treatment. The tobacco or the treatment gas supplied to the
reactor and/or the decompression step are carried out in such a way
that the discharged tobacco which is thereafter supplied to a
subsequent heat treatment has a temperature, at introduction to the
heat treatment step, below 0.degree. C. This is achieved by
precooling the treatment gas prior to supplying it to the autoclave
or cooling the treatment gas while supplying it to the autoclave
and/or additionally cooling the autoclave and/or precooling the
tobacco and/or injecting subcooled or liquefied treatment gas into
the autoclave. The process includes multistage treatment gas
whereby supply and decompression steps are carried out in a
cascade-like manner.
Inventors: |
Ziehn; Klaus-Dieter (Pinneberg,
DE) |
Assignee: |
H.F. & Ph.F Reemtsma GmbH &
Co. (Hamburg, DE)
|
Family
ID: |
6196982 |
Appl.
No.: |
06/602,425 |
Filed: |
April 20, 1984 |
Foreign Application Priority Data
|
|
|
|
|
Apr 21, 1983 [DE] |
|
|
3314474 |
|
Current U.S.
Class: |
131/296;
131/292 |
Current CPC
Class: |
A24B
3/182 (20130101) |
Current International
Class: |
A24B
3/18 (20060101); A24B 3/00 (20060101); A24B
003/18 () |
Field of
Search: |
;131/900,292,290,291,294,296,300 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Millin; V.
Assistant Examiner: Macey; H.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
What is claimed is:
1. In a process for improving the fillability of tobacco by
treatment with a treatment gas containing at least one of the
following: nitrogen gas, argon gas or a mixture thereof at
pressures up to 1000 bar in an autoclave, decompressing the
tobacco, and subjecting the tobacco to a heat treatment, the
improvement comprising:
supplying the autoclave with both tobacco and treatment gas and
decompressing the treated tobacco in such manner that the
decompressed tobacco supplied to the subsequent heat treatment has
an inlet temperature for the heat treatment of below 0.degree. C.,
said treatment gas being non-polar.
2. A process according to claim 1, comprising cooling the treatment
gas not later than when it is supplied to the autoclave.
3. A process according to claim 2, comprising cooling the autoclave
in which the tobacco is treated with the treatment gas.
4. A process according to claim 1 comprising cooling the autoclave
in which the tobacco is treated with the treatment gas.
5. A process according to claim 1, comprising cooling the tobacco
prior to its introduction into the autoclave.
6. A process according to claim 4, comprising cooling the tobacco
prior to its introduction into the autoclave.
7. A process according to claim 1, comprising injecting subcooled
or liquefied treatment gas into the autoclave during the treatment
of the tobacco with the treatment gas.
8. A process according to claim 1, said process further
comprising
providing a plurality of autoclaves;
cascading said autoclaves wherein treatment gas from one autoclave
under a high pressure is introduced into at least one other
autoclave, said other autoclave being at an initial pressure less
than said one autoclave, whereby said one autoclave is decompressed
while said other autoclave is pressurized.
9. A process according to claim 8, said process further
comprising:
carrying out the pressurization and the decompression in a stepwise
manner, the pressurization including forcing additional treatment
gas into a said other autoclave during the final compression stage
to obtain the desired final pressure.
10. A process according to claim 9, said process further
comprising:
additionally cooling the treatment gas supplied from a said one
autoclave during the transfer of said gas to a said other
autoclave.
11. A process according to claim 8, said process further
comprising:
additionally cooling the treatment gas supplied from a said one
autoclave during the transfer to a said other autoclave which is at
a lower pressure.
12. A process according to claim 8, said process further
comprising:
charging the autoclave during the final stage of the compression
with subcooled or liquified treatment gas.
13. A process according to claim 1 comprising subjecting the
tobacco to low temperature insulation after decompression and up to
the subsequent heat treatment to prevent premature heating.
14. A process according to claim 1, comprising carrying out the
subsequent heat treatment either with (1) water vapour in the form
of saturated steam or (2) with water vapour having a density of 0.5
to 10 kg/m.sup.3 or (3) with hot air having a temperature up to
440.degree. C.
15. A process according to claim 14 wherein the subsequent heat
treatment is carried out either with (1) water vapour in the form
of saturated steam or (2) with water vapour having a density of 0.5
to 10 kg/m.sup.3.
16. A process according to claim 1, comprising introducing the
treating gas into the autoclave from below or from the side.
17. A process according to claim 1, comprising decompressing the
autoclave via the top or through the bottom after the final
pressure is reached.
18. A process according to claim 1, comprising introducing the
treating gas into an annular space within the autoclave, said
annular space being defined in its outer configuration by the inner
wall of the autoclave and in its inner configuration by a
cylindrical wall having openings leading into the inner part of the
autoclave.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for improving the
fillability of tobacco, such as cut tobacco leaves or ribs or
tobacco additives by treatment with a nitrogen and/or
argon-containing treatment gas at pressures up to 1000 bar in an
autoclave and a heat treatment following the decompression.
2. Background of the Invention
Processes of this type are known from German Pat. No. 2,903,300 and
related Ziehn U.S. Pat. No. 4,289,148, the entire disclosure of
which is hereby incorporated by reference and relied upon and
German Pat. No. 3,119,330 and related Ziehn U.S. application Ser.
No. 378,390 filed May 14, 1982, now U.S. Pat. No. 4,461,310, the
entire disclosure of which is hereby incorporated by reference and
relied upon. In these processes, during the high pressure gas
treatment with nitrogen, working takes place in the range 150 to
1000 bar and during treatment with argon in the pressure range 50
to 800 bar.
The problem of the present invention is to improve these known
processes and in particular to perform them economically and
continuously. A further problem of the invention is to improve the
fillability of those tobacco types or additives, which cannot be
swollen in a satisfactory manner by the known processes.
Hereinafter, the term tobacco not only covers cut tobacco leaves
and ribs, but also torn tobacco leaves, such as are used in cigar
manufacture, as well as other tobacco products and additives.
Tobacco additives, inter alia, include the following fibrous
natural products: buds of Cinnamomum Lassia, seeds of Apium
graveoleus, cellulose fibres, Eugenia caryophyllata, seeds of
Cumium cymium, various dried fruits of, e.g., apples, plums, figs,
as well as roots of Glycyrriza glabra, as well as Folium
liatris.
SUMMARY OF THE INVENTION
According to the present invention, the above-problem is solved by
the present process which provides for improved fillability of
tobacco, such as cut tobacco leaves or ribs or tobacco additives by
treating the tobacco with a nitrogen and/or argon-containing
treatment gas at pressures up to 1000 bar in an autoclave,
conducting a decompression step and a heat treatment step
thereafter wherein the treatment gas supply and/or the
decompression step are carried out in such a way that the
discharged tobacco which is supplied to a subsequent heat treatment
has a temperature at introduction to the heat treatment of below
0.degree. C.
The invention is described in greater detail hereinafter relative
to the examples and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a diagrammatic view of an installation for performing the
process according to the invention.
FIG. 2 a diagrammatic view of a preferred embodiment of the cascade
principle.
FIG. 3 a graph showing the dependence of the fillability
improvement FCI in % on the inlet temperature of the tobacco for
the heat treatment.
DETAILED DESCRIPTION
The present invention relates to a process for improving the
fillability of tobacco, such as cut tobacco leaves or stems and
tobacco additives by treating the tobacco in an autoclave with a
nitrogen and/or argon-containing gas at pressures to 1000 bar, with
subsequent decompression and a heat treatment. According to the
invention, the tobacco or treatment gas supplied to the reactor
and/or the decompression step are carried out in such a way that
the discharged tobacco which is thereafter supplied to a subsequent
heat treatment has a temperature, at introduction to the heat
treatment step, below 0.degree. C. This is achieved by precooling
the treatment gas prior to supplying it to the autoclave or cooling
the treatment gas while supplying it to the autoclave and/or
additionally cooling the autoclave and/or precooling the tobacco
and/or injecting subcooled or liquefied treatment gas into the
autoclave. The invention more particularly relates to a process
with multistage supply and decompression steps carried out in a
cascade-like manner.
Preferably, one or more of the following features are also included
in the basic novel process.
1. The treatment gas is precooled prior to being supplied to the
autocalve or it is cooled while it is supplied to the
autoclave.
2. There is additional cooling of the autoclave in which the
tobacco is treated with treatment gas.
3. The tobacco is precooled prior to its introduction into the
autoclave.
4. Subcooled treatment gas is injected into the autoclave during
the treatment of the tobacco with the treatment gas.
5. The action with the treatment gas and the decompression are
performed in cascade-like manner with a plurality of autoclaves.
This cascade-like process is conducted in such a way that the
pressure build-up of the treatment gas in autoclave is obtained by
the stepwise use of a treatment gas at a higher pressure, from
another autoclave, to an autoclave at a lower pressure thereby
resulting from the decompression of one autoclave while raising the
pressure of the other.
6. The pressure increase and decrease takes place in stepwise
manner with additional treatment gas being forced into one
autoclave during its final compression stage to increase the
pressure up to the final desired pressure.
7. The treatment gas which is supplied in a cascadelike manner from
one autoclave under high pressure to another autoclave under a
lower pressure is additionally cooled during the transfer of gas
from the autoclave under higher pressure to the autoclave under
lower pressure.
8. During the final stage of the compression, the autoclave is
charged with subcooled or liquified treatment gas.
9. After decompression and up to the subsequent heat treatment, the
tobacco is protected with low temperature insulation to prevent any
heating.
10. The subsequent heat treatment is carried out with water vapor
in the form of saturated steam or with water vapor having a density
of 0.5 to 10 kg/m.sup.3 or with hot air having a temperature of up
to 440.degree. C.
11. The treating gas is introduced into the autoclave from
underneath the autoclave or from a side of the autoclave.
12. After the final pressure has been reached, the autoclave is
decompressed via the top or through the bottom of the
autoclave.
13. The treating gas is introduced into an annular space within the
autoclave. The annular space is defined in its outer configuration
by the inner wall of the autoclave and in its inner side by a
cylindrical wall having openings leading into the inner part of the
autoclave.
It has surprisingly been found that it is important for obtaining
an improvement in the fillability or a high degree of swellability
that after pressure treatment, i.e., after decompression of the
autoclave and discharge therefrom, the tobacco is supplied to the
subsequent heat treatment such that the tobacco has a temperature
at inlet of lower than 0.degree. C. If the tobacco is discharged
from the autoclave at a higher temperature, or if the tobacco
absorbs heat after discharge and, e.g., when being conveyed over a
long distance from the autoclave to the heat treatment station,
there are obtained less satisfactory swelling effects.
The knowledge that the supplying of the autoclave with the tobacco
or with the treatment gas and/or the decompression thereof must be
controlled in such a way that the discharged tobacco supplied to
the subsequent heat treatment has an inlet temperature for the heat
treatment below 0.degree. C. is surprising in connection with
obtaining a good swelling effect, particularly in the case of a
product which per se can only undergo limited swelling.
The substantial advantage of maintaining a minimum inlet
temperature of the tobacco from the heat treatment of below
0.degree. C. is that improved swelling effects are obtained
compared with a tobacco having a higher inlet temperature during
the heat treatment and in particular better fillability levels can
be obtained, particularly with material which can only undergo
limited swelling.
Several means are suitable for obtaining the minimum inlet
temperature of the tobacco which is required for the subsequent
heat treatment according to the present invention. According to the
invention, the autoclave temperature can be reduced, e.g., by means
of a jacket cooling, to such an extent that part of the compression
heat is removed.
The tobacco can be introduced in the reactor and precooled
preferably to just above the freezing point of the water contained
in the tobacco.
According to a preferred embodiment of the present novel process,
the treatment gas can be supplied to the autoclave in cooled form.
This compensates for the heat of compression which builds up. As a
consequence, the discharge temperature of the tobacco following
decompression is considerably reduced.
The treatment gas may be cooled either prior to being introduced
into the autoclave or while the gas is being introduced to
autoclave. In the latter case, it is possible to cool the nitrogen
or argon within the autoclave by circulating the gas through
cooling means located outside of the autoclave.
Preferably and thus advantageously, the treating gas is introduced
into an annular space within the autoclave. The annular space is
defined on its outer side by the inner wall of the autoclave and on
its inner side by a cylindrical wall having openings. The openings
lead into the inner part of the autoclave. The main advantage of
introducing the treatment gas through the openings of the cylinder
wall forming the annular space is a better and more even
distribution of the treating gas within the autoclave. The even gas
distribution avoids forming a dense compact tobacco mass.
To avoid the formation of compacted or adhering material, it is
also possible to introduce the treating gas into the autoclave from
below or from the side of the autoclave. Alternatively, the
formation of compact material is also avoided if, after having
reached the final pressure, the treating gas is withdrawn either
via the top or through the bottom of the autoclave.
A particular embodiment of the invention is quite economic. A
procedure is employed wherein the compression and decompression are
performed in cascade-like manner in a number of stages. Thus, an
autoclave at a relatively low pressure is charged with a treatment
gas under a higher pressure coming from another autoclave, which
gas is expanded in stages. Such a cascade-like compression and
decompression not only serves to bring about a better utilization
of the energy expended for the compression in the sense that the
treatment gas under the higher pressure at the time of its
decompression is used for the pressure build-up of the treatment
gas in another reactor, but also for introducing a cooler treatment
gas for the reactor filled with treatment gas by the reactor under
a higher pressure, because the expansion enthalpy mainly leads to a
cooler gas and to a much lesser extent to a cooling of the reactor
wall and tobacco.
When the pressure increases and decreases occur in stepwise
fashion, it is necessary to force the treatment gas into the final
compression stage to attain the desired final pressure.
It is also advantageous if the gas entering the lower pressure
reactor in the case of cascade-like pressure compression is
additionally cooled during the transfer. This cooling can, for
example, be obtained by means of the expansion enthalpy from the
final decompression stage of a reactor.
It is also advantageous according to a further development of the
inventive process, when the treatment gas or part thereof is
supplied to the final compression stage in a subcooled form.
All these possibilities for the action and supply of the treatment
gas and its decompression, including the supply of a precooled
tobacco can be carried out individually or in combination, all that
is important is that the minimum temperature of the tobacco
supplied to the heat treatment is below 0.degree. C. The swelling
effect is improved by still lower inlet temperatures of the tobacco
or the treatment material.
If the tobacco discharge temperature from the autoclave corresponds
to the minimum tobacco inlet temperature for the heat treatment or
is somewhat lower than the latter, it must be ensured that the
tobacco is immediately supplied to the heat treatment and does not
absorb heat on the way from the autoclave to the heat treatment
station. since in the case of continuous installations with a
number of autoclaves, the conveying paths up to the heat treatment
station are relatively long, it is necessary according to another
aspect of the invention to insulate the tobacco against heat
absorption following decompression. The insulation means that after
discharge from the autoclave, the tobacco temperature does not rise
above the tobacco inlet temperature for the heat treatment required
by the present invention. This can, for example, be achieved by
storing the freshly discharged tobacco in covered insulating
vessels or by supplying the freshly discharged tobacco to the heat
treatment by means of a cooling tunnel, the energy for maintaining
a lower ambient temperature in the cooling tunnel, e.g., being
obtainable through the decompression enthalphy of the final stage
of cascade decompression.
The times or periods for building up the pressure should be
selected in such a way to avoid too strong a heating of the
tobacco. The time period during which the autoclave is decompressed
(pressure release time) is in the range of about 0.5 minute to
about 10 minutes.
In the diagram of FIG. 1, there are in all 12 autoclaves, 1, 2 . .
. 12, which are supplied with treatment gas by means of a main line
20 and branch lines 21. This treatment gas passes from a liquid gas
container 24, which, e.g., contains liquid nitrogen, via an
evaporator 26 into a storage tank 28, from where the treatment gas
is supplied under a certain initial pressure of, e.g., 2 to 10 or
even 12 bar via a line 30 to a compressor 22 and from there is
forced into the main line 20.
The reactors are also interconnected by means of connecting lines
23, the opening and closing of the valves for the connecting lines
being electronically controlled.
As indicated by the arrow 40, the individual autoclaves are
supplied with tobacco from above. The tobacco has a random moisture
content of 10 to 30% by weight water and preferably 12 to 24% by
weight water, whilst the tobacco additives, such as cloves, can
appropriately have a higher moisture content of, e.g., 50%. The
tobacco feed-in temperature can correspond to ambient temperature.
However, as a function of the pre-treatment of the cut tobacco, it
can also be higher and in the case of an inventive variant of the
present process, can also be just above the freezing point of the
water present in the tobacco.
Following the pressure treatment and the decompression of the
treatment gas, the tobacco is supplied by conveyor belts 42 to a
dosing and distributing device 44 where, spread out on a belt, it
is supplied to a heat treatment station 46. The latter is
preferably a saturated steam treatment tunnel, but can also be a
station with a different heat supply.
in the process according to the invention, it is important that in
connection with heat treatment station 46, the inlet temperature of
the tobacco for the heat treatment is below 0.degree. C. The
tobacco swells spontaneously on passing through the heat treatment
station. As a function of the temperature, the saturated steam can
have a water vapour density of 0.5 to 10 kg/m.sup.3. Higher
saturated steam densities or a higher temperature saturated steam
should generally be avoided for economic reasons and to prevent
damage to the tobacco, although it is important during said heat
treatment to supply the tobacco which is at its minimum inlet
temperature of below 0.degree. C., with thermal energy as rapidly
as possible, so that the swelling effect assumes a maximum
value.
The swollen tobacco made overmoist by the saturated steam is then
passed through a drying tunnel 48 and a following cooling means 50,
in order to be removed for further processing at the desired
processing moisture content and temperature.
In order to prevent heating of the tobacco, which is, e.g.,
discharged from the autoclave at a temperature of -40.degree. C.,
the conveyor belts 42 can be surrounded by a cooling tunnel 52. In
place of cooling tunnel 52, the tobacco can also be conveyed in
thermally insulated storage containers (not shown), it then being
supplied batchwise to the heat treatment station 46 by means of
dosing device 44. This permits a more flexible operation.
According to a preferred embodiment of the invention, it is
possible to supply by means of a separate line 54 liquid treatment
gas directly to the line system 21, preferably during the final
stage of the compression. In line 30, upstream of compressor 22 or
in lines 20 or 21, it is also possible to additionally cool the
treatment gas by a cooling unit (not shown). Cooling units can also
be provided in the connecting lines 23 between the individual
autoclaves.
In the case of the exemplified representation of the preferred
cascade principle according to the invention shown in FIG. 2,
working takes place with four autoclaves, pressure build-up and
decompression taking place in each case in four stages, i.e. 8
stages in all.
In the first stage, autoclave 1 is at a pressure of 750 bar and for
decompression purposes, is connected via connecting line 23 to
autoclave 2, which is under a pressure of 220 bar and is also
subject to compressed gas action. Autoclave 3, which is at normal
pressure and which has just been supplied with tobacco, is
connected by a further connecting line with autoclave 4, which
contains a treatment gas under a pressure of 220 bar and is to be
further expanded.
In stage 2, a pressure compensation has taken place between
autoclaves 1 and 2, whose treatment gas is in both cases at 410
bar. Autoclaves 3 and 4 have a pressure of 100 bar as a result of
the pressure compensation. The further decompression of autoclave 1
takes place by means of a connection with autoclave 3 and autoclave
2 is further supplied with compressed gas by means of the
compressor or is supplied with the liquified treatment gas.
Autoclave 4 is expanded and the treatment gas is led off into tank
28. The expansion enthalpy can be used for cooling the treatment
gas.
A pressure compensation between autoclaves 1 and 3 has been
achieved in stage 3 where the treatment gas in autoclave 1 has
dropped from 410 to 220bar and the treatment gas in autoclave 3 has
risen from 100 to 220 bar. Autoclave 2, which has been brought to
the final treatment pressure of 750 bar is now ready for
decompression. The gas treated in autoclave 4 is discharged and is
replaced by new, optionally precooled tobacco. By connecting
autoclave 1 to autoclave 4, the former is further expanded and the
latter is supplied again with treatment gas. Autoclave 3 is subject
to further action through the connection with autoclave 2, which is
ready for compression.
In stage 4, equilibrium has been established between autoclave 1
which is in the decompression stage and which has dropped to 100
bar and autoclave 4 which has gone up to 100 bar, whilst autoclaves
2 and 3 have been brought to 410 bar by corresponding compensation.
Autoclave 1 is expanded and the treatment gas is transferred into
the storage tank 28, optionally using the expansion enthalpy for
cooling a treatment gas supplied at another point. Autoclave 3 is
supplied with further optionally precooled treatment gas to a
pressure of 750 bar, unless liquid gas is injected according to a
preferred form of the process according to the invention. The
further stages 5 to 8 are carried out in the same way as described
hereinbefore.
The process can comprise, consist essentially of, or consist of the
recited steps with the stated materials.
EXAMPLE 1
30 kg of a finished tobacco mixture are treated in a 200 liter
autoclave with nitrogen up to a final pressure of 750 bar, whilst
maintaining different inlet temperatures during the heat treatment.
The mean values of the percentage fillability improvement obtained
from 2 to 4 mixtures are given in the graph according to FIG. 3,
where they are plotted against inlet temperatures determined in the
conventional manner. The curve clearly shows the excellent
fillability improvement of filling capacity increase (FCI in
%).
EXAMPLE 2
To show the influence of cooling the mantle of the autoclave with
respect to improving the filling capacity the following test was
made:
30 kg of a cut tobacco mixture were treated in a 200 liter
autoclave with nitrogen up to a final pressure of 750 bar by
maintaining different temperatures of the cooling water of the
autoclave. All other parameters were identical for all runs. The
results are as follows:
______________________________________ Temperature of Temperature
of the Tobacco After Filling the Cooling Removal From The Capacity
Water in .degree.C. Autoclave in .degree.C. Increase in %
______________________________________ +12 -40 +65 +31 -10 +52 +50
+10 +39 ______________________________________
EXAMPLE 3
To show the influence of insulation the tobacco removed from the
autoclave against warming up to room temperature the following
tests were made:
30 kg of a cut mixture were treated in a 200 liter autoclave with
nitrogen up to a final pressure of 750 bar with constant cooling of
the mantle of the autoclave. After release of the pressure the
tobacco was subjected to the heat treatment directly after removal
from the autoclave, i.e., ex autoclave, after storing at a
temperature of -50.degree. C. for a period of 20 hours and after
storing for a period of 20 hours at ambient temperature. The
results are as follows:
______________________________________ Temperature of Filing
Capacity the Tobacco Improvement in .degree.C. %
______________________________________ Ex autoclave -45 +72 After
20 hours -50 +70 storing at -50.degree. C. After 20 hours +5 +35
storing at room temperature
______________________________________
* * * * *